In multicast service, path discovery for multicast are mostly implemented according to control layer protocols, that is, the path discovery for multicast are generally implemented through multicast routing, instead of paths through which actual multicast data streams pass. In some cases, the multicast routing is not necessarily consistent with the multicast data stream, and therefore, it is required to perform detection on multicast paths according to actual multicast data streams.
In the prior art, a multicast path detection method is provided. As shown in FIG. 1, a multicast network includes Maintenance association End Point (MEP) MEP1, MEP2, and MEP3, and Maintenance association Intermediate Point (MIP) MIP1 and MIP2. MEP1 is a source MEP, and MEP2 and MEP3 are target MEPs. The source Maintenance association End Point MEP1 sends a Link Trace Message (LTM) to the target maintenance association end point MEP2, and the LTM message carries a physical address of MEP2. After receiving the message, the target maintenance association end point MEP2 and the maintenance association intermediate point MIP1, through which the LTM message passes, send a Link Trace Reply (LTR) message to the source maintenance association end point MEP1, and the source maintenance association end point MEP1 determines a path to the target maintenance association end point according to the received LTR message.
In the prior art, the path detection method can only detect the multicast path leading from the source maintenance association end point MEP1 to one target maintenance association end point MEP each time, and cannot detect the multicast paths leading from the source maintenance association end point to multiple target maintenance association end points at the same time.